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Getting newer slot 1 P3 to work in unsupported board

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First post, by aderius

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Hi all,

I have a Dell SE440BX-3 motherboard, currently has a P3 550/512kb/100 mhz/2.0v CPU, slot 1. I bought a P3 900/256kb/133 mhz/1.65v. I am using bios A07. System gets power, but just won't post. The VRM on the board is SC1185ACSW which supports 1.3-3.5v. I suspect it may be an incompatibility with the FSB speed. Is there any way to check this/mod the new CPU to work on this board?

Reply 1 of 2, by dionb

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P3 900/256kb/133 mhz/1.65v

Something is wrong in this description. 900MHz must be 9x100MHz FSB; a P3 can only work with whole or half multipliers, with 133MHz FSB you can do either 6.5x133=866MHz or 7x133=933MHz.

So as to be unambiguous: what is the S-Spec of this CPU?

Also, you are using a rather old BIOS, the latest one in your own link is A11. Have you tried that?

Reply 2 of 2, by aderius

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dionb wrote on 2025-07-28, 20:37:
Something is wrong in this description. 900MHz must be 9x100MHz FSB; a P3 can only work with whole or half multipliers, with 133 […]
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P3 900/256kb/133 mhz/1.65v

Something is wrong in this description. 900MHz must be 9x100MHz FSB; a P3 can only work with whole or half multipliers, with 133MHz FSB you can do either 6.5x133=866MHz or 7x133=933MHz.

So as to be unambiguous: what is the S-Spec of this CPU?

Also, you are using a rather old BIOS, the latest one in your own link is A11. Have you tried that?

Ahh, wrong CPU! It is indeed 866 mhz. Dell locks out faster CPUs than 600 mhz from the A08 update and on. This is the CPU.

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